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Mechanical Evaluation of Polycarbonate Polyurethane for Long-Term Orthopedic Implant Applications
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| 자료유형 | 학위논문 |
|---|---|
| 서명/저자사항 | Mechanical Evaluation of Polycarbonate Polyurethane for Long-Term Orthopedic Implant Applications. |
| 개인저자 | Ford, Audrey Christine. |
| 단체저자명 | University of California, Berkeley. Mechanical Engineering. |
| 발행사항 | [S.l.]: University of California, Berkeley., 2019. |
| 발행사항 | Ann Arbor: ProQuest Dissertations & Theses, 2019. |
| 형태사항 | 186 p. |
| 기본자료 저록 | Dissertations Abstracts International 81-04B. Dissertation Abstract International |
| ISBN | 9781085792158 |
| 학위논문주기 | Thesis (Ph.D.)--University of California, Berkeley, 2019. |
| 일반주기 |
Source: Dissertations Abstracts International, Volume: 81-04, Section: B.
Advisor: Pruitt, Lisa. |
| 이용제한사항 | This item must not be sold to any third party vendors.This item must not be added to any third party search indexes. |
| 요약 | There are currently over 2 million total joint replacement procedures completed every year worldwide. The number of total joint replacement procedures is predicted to grow. At the same time, the percentage of younger, more active patients undergoing joint replacement procedures is also predicted to increase. Such predictions motivate a need for joint replacements to last longer and perform better in more active patients. The greatest challenge for current joint replacement device designs is wear-related failures. One potential solution to improve wear performance is to use alternative materials with superior wear performance. Polycarbonate polyurethane (PCU) has been proposed as an alternative material to improve the performance of joint replacements. It is softer and more elastomeric than the current standard polymer, ultra-high molecular weight polyethylene. It has been hypothesized that, due to its lower elastic modulus, PCU will have improved lubrication performance, reducing wear. Historically, improvement to ultra-high molecular weight polyethylene wear performance has come at the expense of fracture resistance. Therefore, in the highly cyclic loading environment of a total joint replacement, the fatigue and fracture properties are also important to consider.This thesis evaluated the long-term mechanical performance of PCU in orthopedic implant applications. First, we characterized the fatigue crack growth mechanisms in PCU as a function of loading, frequency, hydration, and thermal annealing treatment. We found highly time-dependent behavior as mechanisms of crack growth and failure changed with loading regime. Second, we looked at changes in the structural organization of PCU as a function of thermal treatments and strain. We found trends of increasing ductility with increasing annealing temperature and increasing hydrogen bonding in the ordered hard domain. The amount of hydrogen bonding decreased with increasing strain. Finally, we used an 3D-transient elastohydrodynamic lubrication model to characterize the lubrication regimes in PCU during a simulated gait cycle. Our model contradicts the optimistic predictions of 1D-steady state modeling and may explain the disconnect between early modeling and the experimental wear results for PCU. Moving forward, this work serves as a foundation for many questions that still need to be answered to understand the fatigue, fracture, and tribological performance of this complex material in long-term clinical implant applications. |
| 일반주제명 | Mechanical engineering. Biomedical engineering. Biomechanics. |
| 언어 | 영어 |
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: 이 자료의 원문은 한국교육학술정보원에서 제공합니다. |
